Buy the Sword Barrack first. As you level up your barracks, you can store more soldiers (up to 4 at level 12).
To manage your army like a pro without external scripts, follow this established gameplay "script": Control Army Script
Check out these guides for a full breakdown of early-game progression and hidden mechanics: Buy the Sword Barrack first
You can increase your luck by unlocking new items in the Index. Every new item discovered grants a +1% luck boost, which helps with rare drops like armor or the Golden Key from the Golden Golem. Control Army Script